I'm confused as to how this will actually save them any money over time. Won't it just encourage everyone who wants to quit to wait until the 401k payout date to the extent possible and then do it all at once?
They could fire a lot of people before the end of the year...
People don't always optimize. I've known two people in this situation who left money on the table. Even if you quit on Jan 30'th, that's one month of money left on the table.